Television apparatus



Oct. 28, 1930. L. T'SCHORNER TELEVISION APPARATUS Filed; Sept. 19. 1928 FIG-2.

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Patented Oct. 28, 1930 UNITED STATES LUDWIG rsonornvnn, or vrnnne, AUSTRIA.

TELEVISION APPARATUS Application fil ed September 19, 1928, Serial No. 306,954, and in Austria August 1,1928.

This invention relates to a device for the telegraphic transmission of visual representations of objects and images.

In television it is advantageous. to divide the picture or image into a plurality of elementary parts each of which is transmitted independently of the others in order to obtain the necessary transmission speed, or in other words, the required number of light impulses per unit time in the receiver. This is effected by superimposing on a single carrier wave a plurality of modulated frequencies, preferably low ones, each one of which corresponds to a part of the divided image.

The individual waves are generated by exploring different elementary parts of the image. 7

The division of the image in the transmission apparatus is according to the invention effected by the use of a rotary disc provided with spiral rows of apertures, in combination with a transparent screen provided with parallel lines which is interposed between the disc and th'eimage. The disc apertures move substantially perpendicularly across the screen lines and produce dots of light the size of which depends on the spacing of the screen lines. The screen can also be adapted to move perpendicularly to the lines in which case the effect can be modified, larger dots being produced when screen and apertures move in the same direction than when they move in opposite directions. Preferably the screen lines correspond in width to the diameter of the screen apertures.

The disc is provided with several row-s of apertures, and each spiral row explores a different part of the object or image. The light impulses of the different spirals are 4 concentrated in known manner on photoelectric cells, and the electric impulses thus produced are amplified and then superimposed, each one with its particular frequency, on the transmitted carrier wave. The differcut wave lengths are obtained by providing the screen with a different line spacing for each particular spiral so as to vary the number of light impulses per unit time.

Fig. 1 of the accompanying drawings represents a view of the rotary disc,

I Fig. 2 is a part view of the screen, Fig. 3 is a complete View of thescreen, and Fig. is asectional view showing the cooperative mounting of the perforated disc and the screen. The device by the use of which the image .to be transmitted is explored consists of a rotary disc 1 or a drum provided with spiral rows 2-, 3, 4L and 5 of apertures. At least two rows of apertures are required in orderv to obtain the necessary transmission speed. Each spiral is used for the exploration of a separate part, in the present instance one quarter, ofthe image 6. Interposed between the disc and the image is a transparent screen 7 (Fig. the parallel lines 8 of which cause the light transmitted through the disc apertures to be. interrupted as many times PATENT, OFFICE as there are lines on the screen. The width 7 of the screen lines preferably corresponds" 12 may have a gradual increasing line spacing. Since the spacing can be varied at will, the frequencies obtained from the spirals can be easily differentiated. Each screen part can, moreover, be adapted for independent movement so as to allow the effective line spacing to be varied by movingthe screen part in the same or in opposite direction to the disc aperture. I

The receiver is provided with .a disc 1 which is identical with that of the transmitter. Light is transmitted through the apertures from lamps the number of'which corresponds to that of the spiral. The lamps produce at identical points the same light intensity as obtains in the transmitter. Electric discharge lamps are used, and the intensity of the light varies with the strength of the current in the received low frequencies.

The various frequencies are filtered in the receiver and passed on to difierent lamps each of which supplies light to the respective aperture row in the disc 1. For filtering out the oscillations from the carrier wave a piezoelectric crystal is employed, preferably a tuned quartz crystal.

I claim:

1. In a television apparatus, the combination With a rotary disc placed in front of the image and formed with apertures arranged in spiral rows so as to transmit light through said aperturesto different parts of the image, of a transparent screen arranged'between the disc and the image and ruled With parallel lines placed perpendicularly to z-t-he, moves ment of the screen apertures.

2. A structure as claimed in claim 1Iwherein the screen lines are placed differently for each row of disc apertures;

3. A structure as claimed in claim 1 Wherein the screen is movable in a direction-perpendicularly 'to the lines.

L -DWIe TSGHC'RNER. 

